One way to do this is to filter the directory of files by some user input. A GUI would be a nice user friendly way, but if you don't know how to make a GUI, then you could just do it in an mfile. You might end up with something like
subjectnum = input('Input subject number: '); % enter it in single quotes
condition = input('Input condition: '); % also enter in single quotes.
files = dir;
match = strfind({files.name},subjectnum);
idx = find(not(cellfun('isempty',match)));
subfiles = {files(idx).name};
match = strfind(subfiles,condition);
idx = find(not(cellfun('isempty',match)));
filterfiles = subfiles(idx);
now filterfiles has only the files that you want to process.
